Conclusion: impact of phenylephrine on cardiac output is related to preload dependency. When the heart is preload independent, phenylephrine boluses induce on average a decrease in cardiac output. When the heart is preload dependent, phenylephrine boluses induce on average an increase in cardiac output.
How does phenylephrine affect cardiac output?
Phenylephrine increases cardiac output by raising cardiac preload in patients with anesthesia induced hypotension.
Why does phenylephrine decrease heart rate?
Most textbooks and review articles contain a table showing a reduction in cardiac output from phenylephrine (example above). The usual explanation is that phenylephrine increases systemic vascular resistance (afterload), which makes it harder for the heart to pump blood forward.
How does phenylephrine increase heart rate?
As a pure α-agonist, phenylephrine is conventionally considered to solely induce arterial vasoconstriction and thus increase cardiac afterload but not cardiac preload. In specific circumstances, however, phenylephrine may also contribute to an increase in venous return and thus cardiac output (CO).
How does phenylephrine increase systolic blood pressure?
Phenylephrine is a selective α1-adrenergic receptor agonist that increases blood pressure mainly by increasing systemic vascular resistance, without an associated increase in myocardial contractility.
What is preload dependent?
As mentioned in the article,1 preload dependence is defined as a state in which increases in right ventricular and/or left ventricular end-diastolic volume result in an increase in stroke volume. 2. Changes in preload could be due to hypovolemia and/or a decrease in venous tone with increased venous capacity.
Who should not take phenylephrine?
do not take phenylephrine if you are taking a monoamine oxidase (MAO) inhibitor, such as isocarboxazid (Marplan), phenelzine (Nardil), selegiline (Eldepryl, Emsam, Zelapar), and tranylcypromine (Parnate), or if you have stopped taking one of these medications within the past 2 weeks.
When should phenylephrine be avoided?
high blood pressure. significant uncontrolled high blood pressure. a heart attack. coronary artery disease.
What does phenylephrine do to the body?
Phenylephrine is used for the temporary relief of stuffy nose, sinus, and ear symptoms caused by the common cold, flu, allergies, or other breathing illnesses (e.g., sinusitis, bronchitis). This medication works by decreasing swelling in the nose and ears, thereby lessening discomfort and making it easier to breathe.
What is the difference between ephedrine and phenylephrine?
Ephedrine increases heart rate and contractility of the heart muscle and is likely to increase oxygen demand. Phenylephrine reduces heart rate while maintaining blood pressure which may result in a more favorable oxygen supply demand ratio.
Does ephedrine increase heart rate?
Ephedrine alone increased heart rate and glucose and insulin concentrations but did not affect systolic blood pressure.
What is the difference between norepinephrine and phenylephrine?
There are no differences between norepinephrine and phenylephrine in terms of systemic hemodynamics when they are administered as a first-line vasopressor agent in septic shock. Phenylephrine is less effective than norepinephrine to counteract sepsis-related arterial hypotension.
Does phenylephrine raise blood pressure?
To keep your blood pressure in check, avoid over-the-counter decongestants and multisymptom cold remedies that contain decongestants — such as pseudoephedrine, ephedrine, phenylephrine, naphazoline and oxymetazoline. Also, check the label for high sodium content, which can also raise blood pressure.
Does phenylephrine make you sleepy?
Decongestants. Since the main symptom of a cold is congestion in your nose and/or chest, cold medicines usually contain a decongestant ingredient. Examples include phenylephrine and pseudoephedrine. These typically do not cause drowsiness and can make some people feel hyper or more alert.
Is phenylephrine the same as adrenaline?
Phenylephrine is a sympathomimetic drug, which means that it mimics the actions of epinephrine (commonly known as adrenaline) or norepinephrine. Phenylephrine selectively binds to alpha-1 receptors which cause blood vessels to constrict.